1. Technical Field
The present invention relates to power saving devices and power saving methods for a mobile access point.
2. Related Art
A wireless local area network (WLAN) wirelessly communicates with a network using electric waves instead of using cables. The WLAN has been developed so as to solve difficulties of installation, maintenance and mobility of the cables. The demand for the WLAN has increased due to the increase in the number of users requiring wireless communication with a network.
The WLAN includes an access point (AP) and a plurality of stations, i.e. a plurality of mobile stations. The access point functions as a base station of a mobile communication system or as a hub of a wire network system, and sends electric wave signals to the stations so that the users of the stations located within a predetermined transmission distance may access the Internet and the network.
The access point accesses the Internet via wire interfaces, such as an Ethernet interface or the like. Since the access point has to be coupled to the Internet via the wire interface, the access point may not be easily moved from one place to another place, and thus it is provided with power supply voltage via a power cable.
The stations communicate with the access point via wireless interfaces, such as a WLAN interface, or the like, and access the Internet via the access point.
Since the stations communicate with the access point via wireless interfaces, the stations may be easily moved from one place to another place. However, the stations which are moved from one place to another place may not be provided with the power supply voltage via the power cable, and thus they are provided with the power supply voltage from batteries, namely, they are battery powered. However, the stations need power management because of the limited power capacity of the battery.
In a conventional WLAN system, only the stations located within a service area of the access point which is fixed to a location may communicate with the access point.
The station which communicates with the access point via the WLAN has to be located within the service area of the access point which is fixed to a location. Thus, it is inconvenient that the user of the station has to move to the service area of the access point which is fixed to a location so as to communicate with the access point via the WLAN. Wireless Broadband Internet service may solve the above inconvenience.
In the wireless Broadband Internet service, since the conventional access point which is fixed to a location is replaced by a mobile access point, the user of the station does not have to move to the service area of the access point which is fixed to a location so as to communicate with the access point via the WLAN.
In other words, the user of the station may communicate with the mobile access point which is installed on public transportation, such as bus, train and the subway, etc., via the WLAN.
It should be noted that, since the mobile access point is moved from one place to another place, the mobile access point receives power supply voltage from a battery. Thus, the mobile access point requires a power saving mechanism so as to effectively use the limited power capacity of the battery.